Two lines of work will be pursued. First we will examine the development of the topography of the ganglion cell layer in cats and monkeys. Initial work has provided descriptions of the organization of the ganglion cell layer in late fetal and neonatal life. Present work concerns the retinal distribution of amacrine cells, and the possibility that amacrine and ganglion cells are derived from a single population of precursor cells. We will go on to investigate the role played by competition for synaptic space on the maturation of ganglion cell precursors. Second, we will examine area 17 of cat visual cortex, to define and establish the presence of a group of cells, probably concentrating in layers 2 and 3, which process the activity of the W-class of retinal ganglion cell. This demonstration should be of significance in current debates about the organization of visual cortex in particular, and of sensory cortex in general.